Apparatus for manufacturing three-dimensional objects

ABSTRACT

An apparatus and a method are provided for manufacturing three-dimensional objects by selective solidification of a build material applied in layers. In order to improve the manufacturing process and in particular to optimize heat input, it is proposed to use a heating element having at least two functional openings, one of the at least two functional openings serving as a material passthrough and another of the at least two functional openings serving simultaneously as a radiation passthrough.

The invention relates to an apparatus and a method for manufacturing three-dimensional objects by selective solidification of a build material applied in layers.

A large number of apparatuses and methods for manufacturing three-dimensional objects by selective solidification of a build material applied in layers are known from the existing art. Laser sintering or selective mask sintering, for example, may be recited here. Systems with which a layer manufacturing method of this kind can be carried out are also referred to as “rapid prototyping” systems. These layer manufacturing methods serve to manufacture components built up in layers from solidifiable material such as resin, plastic, metal, or ceramic, and are used, for example, to produce engineering prototypes. Using an additive production method, three-dimensional objects can be manufactured directly from CAD data.

In a layer manufacturing method of this kind, the objects are built up in layers, i.e. layers of a build material are applied successively over one another. Before application of the respective next layers, the locations in the respective layers which correspond to the object to be manufactured are selectively solidified. Solidification is accomplished, for example, by local heating of a usually powdered layering raw material using a radiation source. An exactly defined object structure of any kind can be generated by controlled introduction of radiation in suitable fashion into the desired regions. The layer thickness is also adjustable. A method of this kind is usable in particular for the manufacture of three-dimensional bodies by successively generating multiple thin, individually configured layers.

The build material to be solidified is typically preheated to a temperature that is below the processing temperature. The processing temperature is then attained with the aid of an additional energy input.

In a laser sintering process, for example, a plastic material is preheated to a temperature below the sintering temperature. The energy introduced by the laser then contributes only the differential quantity of heat for fusing the powder particles.

Preheating is accomplished in many cases by heating the build platform. With this heating “from below,” however, the preheating heat flow decreases as the component height increases, due to losses and the increasing volume of the powder charge.

Other methods also result in an undesired irregular temperature distribution in the build material. This also applies in particular to those methods in which preheating is accomplished by heat delivery “from above.” Here devices that can be intermittently heated are placed above the build layer. Complex systems for controlling the heat curve, and other laborious actions, are used in an attempt to achieve a uniform temperature distribution in the build material to be preheated.

An object of the present invention is to improve the manufacturing process, in particular to optimize heat input.

This object is achieved respectively by an apparatus according to Claim 1 and by a method according to Claim 10. Advantageous embodiments of the invention are indicated in the dependent claims. The advantages and configurations explained below in connection with the apparatus also apply analogously to the method according to the present invention, and vice versa.

The invention proposes no longer pursuing the cycle-timed manufacturing procedure known from the existing art, in which, within one clock cycle, after an application of material firstly a preheating action and then a selective solidification action occur before another material application is performed in a subsequent new clock cycle. The invention instead proposes a continuous manufacturing process in which application of the build material, preheating, and selective solidification occur simultaneously by local heating of the build material, specifically at different sites on the same objects to be manufactured or also on different objects simultaneously if multiple objects are being manufactured on the build platform.

The apparatus according to the present invention encompasses a build platform, arranged in an X-Y plane, on which at least one three-dimensional object is generated in layers; a heating element, at least partly overlying the build platform, for inputting thermal energy into the build material; and at least one radiation source for selective solidification of build material by local heating. The heating element comprises at least two simultaneously usable functional openings, one of the at least two functional openings being embodied as a material passthrough and another of the at least two functional openings being embodied as a radiation passthrough. According to the present invention the apparatus encompasses a number of drive devices for generating mutually independently controllable relative motions in an X and/or Y direction between at least two of the three following components of the apparatus: the build platform, the heating element, the at least one radiation source.

The method according to the present invention correspondingly encompasses the steps of: generating the at least one three-dimensional object, in layers, on a build platform arranged in an X-Y plane; inputting thermal energy into the build material with the aid of a heating element at least partly overlying the build platform; locally heating build material using a radiation source, for the purpose of selective solidification; and simultaneously causing build material and radiation energy to pass through the heating element using at least two functional openings. According to the present invention the method encompasses generating, by means of a number of drive devices, mutually independently controllable relative motions in an X and/or Y direction between at least two of the three following components of the apparatus: the build platform, the heating element, the at least one radiation source.

A fundamental idea of the invention is the use of a heating element that serves to preheat the build material and is notable for functional openings that serve as a material passthrough and radiation passthrough, therefore as a coating opening for the application of build material and as an exposure opening for local heating of the build material. When a heating element of this kind is moved in suitable fashion relative to the build platform, the application of build material, preheating, and selective solidification can occur simultaneously, i.e. non-cycle-timed, uninterrupted manufacture of the at least one object. In other words, the object or objects is built up continuously, the build rate being determined by the relative motion between the build platform and heating element. The geometric arrangement of the object regions located in the various manufacturing process phases, in particular the spacing of said object regions from one another, is determined by the arrangement of the functional openings in the heating element, in particular by the spacing of said functional openings from one another.

For example, in a first object region the build material in the form of a freshly applied powder charge is being preheated by the heating element, while in a second object region arranged behind the first object region in the motion direction, a layer n is currently being solidified with the aid of radiation energy penetrating through an exposure opening. At the same time, in a third object region that is located behind the second object region in the motion direction, post-heating of the build layer n, just previously solidified there, is being performed by the heating element, while in a fourth object region located behind the third object region, further build material for a subsequent layer n+1, introduced through a coating opening, is being applied onto the layer n that is already present. The object regions can be regions of one object or regions of different objects if multiple objects are arranged on the build platform.

Heat delivery for preheating is accomplished “from above,” so that the disadvantages of heat delivery via the build platform do not occur. At the same time, heat delivery is preferably accomplished not only intermittently, i.e. not only when the heating element is located (as in the existing art) above the build layer for a short time, but instead constantly, this being made possible by the novel continuous working mode. Optimization of heat input is thereby achieved in simple fashion. At the same time, the manufacturing process as a whole is improved.

Thanks to the generation of multiple relative motions between the participating components (build platform, heating element, and radiation source), the time-related effects of the various process conditions in the respective method steps can be optimized and coordinated with one another in a simple and very flexible manner. The manufacturing process as a whole is thereby further improved.

A decoupling of the motion of the radiation passthrough from the motion of the radiation source has proven to be particularly advantageous. In other words, the radiation source can move, over the build platform or over the build material present thereon, at a different speed from the heating element.

In particular when the introduction of radiation energy occurs through the exposure opening in the absence of complete illumination of that opening but when instead a controlled irradiation of the build material arranged beneath that opening occurs within the boundaries of that opening, for example in such a way that a laser heats the build material along a defined trajectory, according to the present invention the radiation source can move, independently of the motion of the heating element and thus independently of the motion of the exposure opening, in the opening region furnished by the radiation passthrough, in such a way that the radiation power can be introduced particularly efficiently.

In a preferred embodiment of the invention this is brought about by the fact that the apparatus comprises, besides a first drive device for generating a first relative motion in an X and/or Y direction between the build platform and the heating element, a second drive device for generating a second relative motion in an X and/or Y direction, independent of the first relative motion, between the radiation source and the heating element.

For further optimization of the process, especially for particularly efficient introduction of the radiation power, the shape, arrangement, and/or size of the exposure openings, in particular the slit width in the principal motion direction, for example the X direction, can be adaptable to the respective process or can also be varied during the manufacturing process. What can be achieved thereby is, for example, that the region respectively located directly beneath an illumination opening and not heated by the heating element is as small as possible. For further optimization, the speed of individual components, in particular the speed of the heating element and thus of the exposure openings, and/or the speed of the radiation source(s), can be varied during the manufacturing process, in particular can be mutually coordinated.

At the same time, the present invention allows elimination of the need for a uniform temperature distribution. Because the manufacturing method has made different degrees of progress at different sites, different temperatures at different sites can be advantageous. For example, in one region a preheating temperature can be advantageous in order to prepare the build material for imminent local heating; in an adjacent region, on the other hand, a post-heating temperature can be present, as is advantageous for achieving certain properties of the already solidified layer, for example in order to prevent warping.

Because the heating element is constantly available, a defined inhomogeneous temperature distribution of this kind can be implemented in particularly simple fashion. In an advantageous embodiment of the invention, the heating element comprises multiple regions capable of different temperature control. This is achieved, for example, with the aid of multiple mutually independently operable heating modules.

An additional heat source for furnishing thermal energy can also be provided, in particular in the form of a radiation source arranged above the heating element. In this case at least one of the functional openings is embodied as a heating opening for additional input of thermal energy. The heating opening can be a functional opening that already performs another function; for example, a radiation passthrough already serving as an exposure opening can serve at the same time as a heating opening.

An embodiment of the invention in which the heating element is of substantially plate-shaped configuration has proven to be particularly advantageous for the transfer of heating energy to the build material. The plate-like shape of the heating element simultaneously makes possible a particularly simple embodiment of the functional openings. Advantageously, the heating element and build platform are embodied in such a way that they overlie one another over the largest possible area, preferably completely, or can be caused during the manufacturing process to overlie one another over as large an area as possible, preferably completely.

In a preferred embodiment of the invention the heating element is arranged above the build platform. In a variant, the heating element is spaced away from the respectively topmost build layer. Heating is accomplished by thermal radiation. In an alternative variant, the heating element touches the topmost build layer. Heating is then accomplished by thermal conduction.

If the build platform is located inside a process chamber that is closed in the operating state, the heating element can then serve as a demarcating wall of the process chamber. In other words, in this case the process chamber is closed off by the heating element. The heating element is then a part of the process chamber.

The coating opening is always an actual opening in the sense of a material perforation. For the exposure opening, however, the heating element need not necessarily be perforated. The exposure opening can also be embodied as a region of suitable material, in the basic body of the heating element, that is suitable for the passage of radiation.

In a preferred embodiment of the invention radiation energy is introduced through the exposure opening but said opening is not completely illuminated. Instead, a targeted irradiation of the build material arranged below said opening occurs, within the boundaries of said opening. The radiation can derive from one or more radiation sources. For example, for local heating of the build material one or more laser beams can execute a linear back-and-forth motion inside the functional opening within the window furnished by the functional opening, or the laser beams are guided in defined fashion inside the window on a nonlinear trajectory, in each case as a function of the structure to be generated. The radiation is guided with the aid of a suitable control system. The build material, previously preheated to a temperature below the processing temperature, becomes locally further heated. The processing temperature is reached with the aid of this additional energy input.

In a particularly advantageous embodiment of the invention at least two radiation sources whose radiation is simultaneously incident, through a shared exposure opening, onto a region of the build layer located therebeneath and uncovered by said exposure opening, are used for energy input. Thanks to the simultaneous use of multiple radiation sources, the radiation energy can be introduced particularly efficiently. At the same time, as described, this makes possible a further optimization of energy delivery.

In a particularly advantageous embodiment of the invention provision is made that each radiation source has associated with it a region of the build layer to be irradiated by it, hereinafter referred to as a “target region.” Adjacent target regions overlap at least in part, forming an overlap region.

In other words, the at least two simultaneously operated radiation sources have control applied to them, in particular are moved in an X and/or Y direction, in such a way that they (also) introduce radiation energy into at least one shared area, i.e. one irradiated by the at least two radiation sources, of the build layer (the overlap region). The at least two radiation sources irradiate the overlap region either simultaneously or successively.

Control is preferably applied to the at least two radiation sources in such a way that the manner in which the radiation regions overlap yields a minimal total processing duration for the build material; more precisely, that the time span required for introduction of the energy necessary for solidification of the build material is minimal. The total manufacturing time span for the three-dimensional objects is thereby shortened. Preferably control is at the same time applied in such a way that the operating times of the individual radiation sources are minimized.

To minimize the processing duration, in a preferred embodiment of the invention the areas to be exposed (the target regions) are firstly subdivided into individual sub-regions, hereinafter referred to as “surface segments,” or such surface segments are selected from the respective target region and in that manner are distinguished from sub-regions that do not need to be exposed. The region simultaneously capable of irradiation by multiple radiation sources and predefined by way of the shape and size of the illumination opening is segmented, for example, in an X and a Y direction.

The necessary dwell time of the individual radiation sources in the respective surface segment is then calculated. Lastly a suitable (preferably the fastest) exposure strategy is identified: the paths that the individual radiation sources describe within the window furnished by the radiation passthrough are identified. Energy input is accomplished, for example, by the fact that a laser beam performs a line-by-line scan or sweep over the relevant surface region, for example forming closely adjacent straight hatching lines, in order to solidify a region of the build layer. This exposure pattern can vary from one layer to another.

Preferably, not only is the exposure strategy for a specific segmentation identified from the standpoint of time-related optimization of the manufacturing process, but the segmentation itself is also carried out in such a way that subsequent exposure can be accomplished particularly efficiently. For example, segmentation is accomplished in consideration of the location of the motion axes of the radiation sources.

The apparatus according to the present invention for manufacturing three-dimensional objects encompasses suitable means for segmenting, for calculating the dwell time, and for identifying the exposure strategy, or is connected to such means or contains corresponding information, in particular control data for applying control to the number of radiation sources for implementing the identified exposure strategy, from an external data source.

The control data used to control the apparatus according to the present invention encompass a data model for describing the objects to be manufactured, or are generated with the use of such a data model. The data model describes not only the division of each object into build layers, but also the location of the objects on the build platform.

With the aid of the present invention it is possible for the data model on which manufacture of the three-dimensional objects is based to be optimized in such a way that the arrangement of the objects on the build platform, or the location of the objects with respect to one another, is selected so that particularly efficient manufacture, especially particularly rapid manufacture, occurs in consideration of the exposure strategy. In a particularly advantageous embodiment of the invention what occurs is therefore not only an optimum selection of the respective individual exposure strategy for each build layer, in particular a time-related optimization of the radiation input, but also, even before that, an optimization, in consideration of the method according to the present invention, of the arrangement on the build platform of the objects to be manufactured.

In a simple variant of the invention the arrangement and size of the functional openings is unmodifiable. It has proven advantageous, for example, to use strip-shaped functional openings that lie parallel to one another. The functional openings are advantageously arranged in the heating element perpendicularly to the direction of relative motion, for example perpendicularly to the X direction or Y direction. Alternatively, it is possible for the functional openings to be arranged obliquely, i.e. at an angle to the motion direction. It is advantageous in the context of the present invention that the shape, arrangement, and size of the functional openings can be adapted to the special aspects of the method. Instead of strip- or slit-shaped functional openings, for example, orifice-shaped functional openings or functional openings of any other shape can also be provided for for all or for individual functions.

In an advantageous embodiment of the invention the shape, arrangement, and/or size of the functional openings is modifiable. For example, it can be advantageous to embody the size of the exposure opening modifiably, in particular when said functional opening serves as an aperture stop, i.e. serves to demarcate the cross section of the introduced radiation. It can likewise be advantageous to embody the size of the coating opening modifiably, in particular when the shape and/or size of said opening directly determine the application location or volume of build material applied for each unit time. A modification of the functional openings can also be accomplished in particular during runtime, i.e. while the manufacturing process is in progress. Additional suitable drive and control devices are then to be provided for this as applicable.

It is not only heat input into the build material that is improved with the present invention. In addition, thanks to a suitable interaction of the arrangement and size of the functional openings and the relative motion between the heating element and build platform, and the manner in which radiation for local solidification of the build material is furnished and/or guided, the manufacturing process can also be carried out particularly efficiently.

This purpose is served by a central control system for the manufacturing process using a data model for description of the object to be manufactured with the aid of the layer building method. The control system encompasses all relevant operations of the manufacturing process that proceeds simultaneously at multiple sites in different manufacturing phases, i.e. manufacturing processes that have made different degrees of progress. In other words, control always occurs in accordance with the actual progress of the manufacturing process, using for this purpose sensor data of suitable sensors, in particular temperature sensors. The control system encompasses in particular control of the heating of the heating element, here optionally the defined control of individual temperature regions. The control system also encompasses control of the drive devices for the relative motions between the heating element, the build platform, and/or the radiation source(s), i.e. also control of the guided radiation sources(s) for local heating of the build material, and control of the furnishing and/or application device for furnishing and/or applying the build material and, if applicable, control of the additional radiation source for controlling the temperature of the build material, as well as also, if applicable, control of the functional openings of modifiable arrangement and/or size.

All calculation operations necessary in connection with control of the layer manufacturing system and with execution of the method according to the present invention are performed by one or more data processing units that are embodied for carrying out said operations. Each of these data processing units preferably has a number of functional modules, each functional module being embodied to carry out a specific function or a number of specific functions in accordance with the method described. The functional modules can be hardware modules or software modules. In other words, insofar as it relates to the data processing unit the invention can be realized either in the form of computer hardware or in the form of computer software, or in a combination of hardware and software. If the invention is realized in the form of software, i.e. as a computer program product, all the functions described are implemented by computer program instructions when the computer program is executed on a computer having a processor. The computer program instructions are realized in any programming language in a manner that is known per se, and can be furnished to the computer in any form, for example in the form of data packets that are transferred via a computer network, or in the form of a computer program product stored in a diskette, a CD-ROM, or another data medium.

An exemplifying embodiment of the invention will be described in further detail below with reference to the drawings, in which:

FIG. 1 schematically depicts an apparatus according to the present invention having a highly simplified process chamber depicted in section;

FIG. 2 is a schematic plan view of a heating element arranged above a build platform;

FIG. 3 shows simplified sectioned depictions of layers of the object to be built up, in different manufacturing phases;

FIG. 4 shows an embodiment of the invention having two radiation sources.

All the Figures show the invention not to scale, merely schematically, and only with its essential constituents. Identical reference characters correspond to elements having an identical or comparable function.

An apparatus 1 for laser sintering is described by way of example on the basis of FIGS. 1 and 2, as an apparatus for manufacturing at least one three-dimensional object by selective solidification of a build material applied in layers. The invention is not, however, limited to this specific method. The invention is also applicable to other additive production methods, for example laser melting, mask sintering, drop on powder/drop on bed, stereolithography, and the like.

An orthogonal coordinate system (X, Y, Z) is utilized in the description of the invention.

Apparatus 1 for laser sintering encompasses a build platform 2, arranged in an X-Y plane, on which a three-dimensional object 3 is generated in layers in known fashion. Build material 4 is a suitable plastic powder. After production of a layer n, in order to produce a new layer n+1 the build platform 2 having the already created and hardened layers is displaced downward over a specific travel length. This purpose is served by a drive device 5 for generating a relative motion in a Z direction, i.e. perpendicularly to the build plane, between build platform 3 and a heating element 6 described later in further detail. This motion in a Z direction is indicated in FIG. 1 by arrow 33. Drive device 5 is, for example, an electric motor.

Between solidification of a layer n and application of new build material 4 for a subsequent layer n+1, provision can be made to remove excess build material 4 from build platform 2. In this case a device suitable for this (not illustrated) is provided, for example in the form of a wiping blade or the like, which advantageously is connected to or interacts with heating element 6.

Apparatus 1 encompasses at least one radiation source 7 that furnishes radiation energy for local heating of build material 4 in order to selectively solidify the latter. The at least one radiation source 7 is, for example, a laser that delivers a laser beam 8 in guided fashion.

Apparatus 1 furthermore encompasses at least one furnishing and/or application device 9 with which build material 4 is furnished and/or is applied onto build platform 2 or onto a build layer that is already present. Furnishing and/or application device 9 is, for example, a device for applying a powder charge. Furnishing and/or application device 9 is connected to a corresponding control system 10 that controls the application of material.

Apparatus 1 further encompasses heating element 6 (already mentioned above) for introducing thermal energy into build material 4, which element constantly at least partly overlies build platform 2 during the manufacturing process. Heating element 6 is of substantially plate-like configuration. It is arranged above build platform 2, being spaced away from the respectively topmost build layer. The spacing is typically between 100 μm and 10 mm. Heating of build material 4 is accomplished by thermal radiation 11 delivered by heating element 6, as depicted symbolically in FIGS. 1 and 3.

Build platform 2 is located inside a process chamber 12, closed in the operating state, that is merely schematically indicated in FIG. 1. Heating element 6 serves here as a demarcation wall of process chamber 12. More precisely, heating element 6 is embodied as part of upper cover 13 of process chamber 12.

Apparatus 1 further encompasses a drive device 15 for generating a relative motion between build platform 2 and heating element 6 in an X and/or Y direction, i.e. in a layer direction. This motion in an X and/or Y direction is indicated in FIG. 1 by arrow 34. Drive device 15 is, for example, an electric motor. The two drive devices 5, 15 are connected to corresponding drive control systems 16, 17.

In the exemplifying embodiment described here, drive device 15 moves build platform 2 relative to the stationary heating element 6. The principal motion direction is the X direction. In the simplest case, the motion of build platform 2 is limited to this principal motion direction. If necessary or advantageous for the manufacturing process, the motion in an X direction can be overlaid by a motion of build platform 2 in a Y direction.

Heating element 6 comprises at least two, in the example depicted in FIG. 1 three simultaneously usable functional openings 18, 19, 20 spaced apart from one another. Functional openings 18, 19, 20 are slit- or strip-shaped, elongatedly rectangular, and lie parallel to one another and perpendicular to the principal motion direction, here the X direction. One of the functional openings is embodied as a material passthrough 18 and another of the functional openings as a radiation passthrough 19. During the production of object 3, both build material 4 and radiation energy, here in the form of laser beam 8, are allowed to pass simultaneously through functional openings 18, 19.

Expressed differently, the one functional opening is embodied as a coating opening 18 for the application of build material 4 onto build platform 2 or onto a build layer that is already present, and the other functional opening is embodied as an exposure opening 19 for simultaneous introduction of radiation energy of the at least one radiation source 7 into the applied build material 4 in order to solidify build material 4.

Radiation energy for local heating of build material 4 is introduced by guiding laser beam 8 through exposure opening 19 on a defined path. Laser beam 8 is guided with the aid of a suitable drive and control device 21. In other words, not only is first drive device 15 used to generate a relative motion in an X and/or Y direction between build platform 2 and heating element 6, but a second drive device 21 is also used to generate a second relative motion in an X and/or Y direction, independent of said first relative motion, between radiation source 7 and heating element 6. In the example illustrated, second drive device 21 serves to move radiation source 7. This motion of radiation source 7 in an X and/or Y direction is indicated in FIG. 1 by arrow 35.

Instead of a stationary heating element 6 having a build platform and radiation source 7 that are movable with respect thereto, in alternative embodiments (not illustrated) the build platform can also be stationary in the X-Y plane; in this case heating shield 6 and radiation source 7 are embodied movably with respect to one another. Alternatively, a stationary radiation source 7 can be combined with a moving heating element 6 and a moving build platform 2 in order to furnish the two desired relative motions.

Heating element 6 comprises multiple heating modules 23, to which control can be applied mutually independently and which are arranged between or next to functional openings 18, 19, 20. All the heating modules 23 of heating element 6 are connected to a heating control system 24. The working principle of heating modules 23 is based, for example, on the principle of electrical induction. Other suitable functioning modes for the heating modules are likewise possible.

In the example illustrated in FIG. 1, apparatus 1 also encompasses an additional heat source in the form of a radiation source 25, arranged above heating element 6, for furnishing thermal energy. This additional radiation source 25 is, for example, an infrared radiator that delivers infrared radiation 26. A suitable control system 27 is provided for this radiation source as well. This additional radiation source 25 has associated with it a dedicated functional opening 20 that thus serves as a heating opening.

A central control system 28 is responsible for controlled execution of the manufacturing method. Control system 28 encompasses for this purpose all the relevant control sub-systems 10, 16, 17, 21, 24, 27.

Various phases of manufacture will be described below with reference to FIG. 3. What is used here is a heating element 6′, different from heating element 6 shown in FIGS. 1 and 2, that possesses three functional openings, namely two coating openings 18, 18′ and one exposure opening 19 arranged between coating openings 18, 18′.

In FIG. 3a , build platform 2, driven by drive device 15, moves through in an X direction beneath first coating opening 18 of heating element 6. Build material 4 for a layer n becomes deposited onto build platform 2.

In FIG. 3b , build platform 2 moves farther in an X direction. Build material 4 that was applied shortly beforehand becomes preheated, by a heating module 23 arranged between first coating opening 18 and exposure opening 19 in the basic body of heating element 6, to a temperature below the sintering temperature. At the same time, in an adjacent object region preheated just previously, additional thermal energy is introduced with the aid of laser beam 8 through exposure opening 19, with the result that the powder particles fuse.

In FIG. 3c , build platform 2 moves farther in an X direction. Before build platform 2 reaches second coating opening 18′, it is moved a requisite travel distance downward in the Z direction, driven by drive device 5. Build material 4 for a further layer n+1 is applied through second coating opening 18′. This object region had just previously been heated again by a further heating module 23′ arranged between exposure opening 19 and second coating opening 18′.

In FIG. 3d , build platform 2 has reached its one reversal point. Layers n and n+1 have been generated. Because there is no longer an exposure opening 19 located above build platform 2, at this moment laser irradiation is no longer taking place. The application of build material 4 also occurs only as long as at least one of the two coating openings 18, 18′ is arranged above build platform 2.

In FIG. 3e , build platform 2 moves through beneath heating element 6 in an X direction, oppositely to the first motion. With the aid of second coating opening 18′, a new application of material for the next layer n+2 has already occurred, as has preheating with the aid of a third heating module 23″. Build platform 2, driven by drive device 5, has previously been moved down again a necessary distance in the Z direction. A local irradiation with laser beam 8 occurs through exposure opening 19 in order to solidify the structure to be generated. First heating module 23 serves for post-heating. Upon a further motion of build platform 2, an application of material for layer n+3 will occur shortly through first coating opening 18.

FIG. 4 illustrates an exemplifying embodiment in which radiation 8 from two simultaneously operated radiation sources 7, 14 is incident, through a shared exposure opening 19, onto a build layer 3 uncovered by that exposure opening 19. For reasons of clarity, heating element 6 is depicted as transparent; in addition, only a single functional opening (exposure opening 19) is illustrated. Each radiation source 7, 14 has a target region 29, 30 associated with it, this association being depicted symbolically with dashed auxiliary lines. The two target regions 29, 30 intersect one another forming an overlap region 31. Control is applied to the at least two radiation sources 7, 14, which again can be lasers, by way of a correspondingly embodied drive and control device 21, so as to result in a minimum total processing duration for the build material. In order to bring about an optimum exposure structure, each radiation source 7, 14 moves on a defined path 32 in an X and/or Y direction, as indicated for radiation source 14 in FIG. 4.

In summary, the invention relates to an apparatus 1 for manufacturing three-dimensional objects 3 by selective solidification of a build material 4 applied in layers, having a build platform 2, arranged in an X-Y plane, on which at least one three-dimensional object 3 is generated in layers; having a heating element 6, at least partly overlying the build platform 2, for inputting thermal energy 11 into the build material 4; having at least one radiation source for selective solidification of build material by local heating, heating element 6 having at least two simultaneously usable functional openings 18, 19, one of the at least two functional openings being embodied as a material passthrough 18 and another of the at least two functional openings being embodied as a radiation passthrough 19. According to the present invention this apparatus 1 encompasses a number of drive devices 15, 21 for generating mutually independent relative motions in an X and/or Y direction between at least two of the three following components: build platform 2, heating element 6, the at least one radiation source 7, 14.

Advantageously, apparatus 1 encompasses a first drive device 15 for generating a relative motion in an X and/or Y direction between build platform 2 and heating element 6, and a second drive device 21 for generating a relative motion in an X and/or Y direction between the at least one radiation source 7, 14 and heating element 6. Advantageously, apparatus 1 encompasses at least two simultaneously operable radiation sources 7, 14 and a control system 21 for applying control to said radiation sources 7, 14 in such a way that their radiation regions 29, 30 overlap.

Advantageously, heating element 6 constantly at least partly overlies build platform 2. Advantageously, heating element 6 and build platform 2 can be caused to overlie one another completely. Advantageously, heating element 6 is of substantially plate-shaped configuration. Advantageously, heating element 6 is arranged above build platform 2; it either is spaced away from the topmost build layer or touches the topmost build layer. Advantageously, build platform 2 is located inside a process chamber 12 that is closed in the operating state, and heating element 6 serves as a demarcating wall of process chamber 12. Advantageously, heating element 6 comprises regions capable of different temperature control. Advantageously, the shape, arrangement, and/or size of functional openings 18, 19, 20 are modifiable. Advantageously, the speed of heating element 6 and/or the speed of the at least one radiation source 7, 14 is modifiable during the manufacturing process.

The invention furthermore relates to a method for manufacturing three-dimensional objects 3 by selective solidification of a build material 4 applied in layers, at least one three-dimensional object 3 being generated, in layers, on a build platform 2 arranged in an X-Y plane; a heating element 6 that at least partly overlies build platform 2 inputting thermal energy 11 into the build material 4; at least one radiation source locally heating build material for selective solidification; and heating element 6, using at least two functional openings 18, 19, 20, allowing build material 4 and radiation energy 8 to pass through simultaneously. The method encompasses generating mutually independent relative motions in an X and/or Y direction, by means of a number of drive devices 15, 21, between at least two of the three following components: build platform 2, heating element 6, the at least one radiation source 7, 14.

All features presented in the specification, in the claims below, and in the drawings can be essential to the invention both individually and in any combination with one another.

LIST OF REFERENCE CHARACTERS

-   1 Apparatus for laser sintering -   2 Build platform -   3 Object, build layer -   4 Build material -   5 Drive direction (Z) -   6 Heating element -   7 Radiation source, laser -   8 Laser beam -   9 Furnishing/application device -   10 Control system for material application -   11 Thermal radiation -   12 Process chamber -   13 Cover -   14 Radiation source, laser -   15 Drive device (X/Y) -   16 Drive control system (Z) -   17 Drive control system (X/Y) -   18 Functional opening, material passthrough, coating opening -   19 Functional opening, radiation passthrough, exposure opening -   20 Functional opening, heating opening -   21 Drive and control device for laser -   22 (unassigned) -   23 Heating module -   24 Heating control system -   25 Radiation source, IR radiator -   26 Infrared radiation -   27 Control system for additional heating -   28 Central control system -   29 First target region -   30 Second target region -   31 Overlap region -   32 Motion path -   33 Motion of heating element in Z direction -   34 Motion of heating element in X and/or Y direction -   35 Motion of radiation source in X and/or Y direction 

1-6. (canceled)
 7. An apparatus for manufacturing three-dimensional objects by selective solidification of a build material applied in layers, the apparatus comprising: a build platform on which at least one three-dimensional object is to be generated in layers, said build platform being disposed in an X-Y plane; a heating element for inputting thermal energy into the build material, said heating element at least partly overlying said build platform; said heating element having at least two simultaneously usable functional openings formed therein, one of said at least two functional openings being embodied as a material passthrough and another of said at least two functional openings being embodied as a radiation passthrough; at least one radiation source for selective solidification of the build material by local heating; and a plurality of drive devices for generating relative motions in at least one of an X or a Y direction between at least two components selected from the group consisting of said build platform, said heating element and said at least one radiation source.
 8. The apparatus according to claim 7, wherein said plurality of drive devices includes: a first drive device for generating a relative motion in at least one of an X or a Y direction between said build platform and said heating element, and a second drive device for generating a relative motion in at least one of an X or a Y direction between said at least one radiation source and said heating element.
 9. The apparatus according to claim 7, wherein said at least one radiation source includes at least two simultaneously operable radiation sources and a control system for applying control to said radiation sources to cause radiation regions of said radiation sources to overlap.
 10. The apparatus according to claim 7, wherein said functional openings have at least one of a shape, a configuration or a size being modifiable.
 11. The apparatus according to claim 7, wherein at least one of said heating element or said at least one radiation source has a speed being modifiable during manufacture.
 12. A method for manufacturing three-dimensional objects by selective solidification of a build material applied in layers, the method comprising the following steps: generating at least one three-dimensional object in layers on a build platform disposed in an X-Y plane; inputting thermal energy into the build material by using a heating element at least partly overlying the build platform; locally heating the build material for selective solidification by using at least one radiation source; allowing the build material and radiation energy to simultaneously pass through at least two functional openings formed in the heating element; and using a plurality of drive devices to generate relative motions in at least one of an X or a Y direction between at least two components selected from the group consisting of the build platform, the heating element and the at least one radiation source. 